cpu: x86 -- Fix --cpu-cap=fpu handling on restore mode

Our CPU_CAP_s are bitmaps so if cpuinfo image is present
but we require only FPU to check we need to check this
bit being sole on comman line.

It was a typo in first place which caused statement to
be false always (it's not a problem though and not a
@stable candidate because with this mistake we fall
into strict match cpu mode).

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>